Atherothrombotic ischemic stroke in patients with atrial fibrillation.

OBJECTIVES: About one in five patients with atrial fibrillation have significant carotid artery disease, but not all strokes are cardioembolic in origin in these patients.

PURPOSE: We investigated stroke sub-types based mainly on clinical, carotid ultrasonographic, and neuroimaging findings in ischemic stroke patients with non-valvular atrial fibrillation (NVAF).

PATIENTS AND METHODS: The etiology of stroke was classified as definite or probable cardioembolic, possible lacunar, or possible atherothrombotic, as proposed by Hart et al. and the TOAST criteria. Clinical features and risk factors (gender, age, diabetes mellitus, hypertension, hyperlipidemia, cigarette smoking, and alcohol consumption) were designated as clinical variables.

RESULTS: One hundred and six of 1938 patients (5.5%) had NVAF. In patients with and without NVAF, hyperlipidemia was more common in patients without NVAF (p<0.001), while the prevalence of other risk factors was not statistically different. On the basis of the TOAST criteria, none of the patients with NVAF could be classified as having had an atherothrombotic stroke. According to the classification by Hart et al., of the patients with NVAF, 49 patients (46.3%) had a definite embolic stroke, 17 (16.0%) had a probable embolic stroke, 12 (11.3%) had a possible atherothrombotic stroke, 17 (16.0%) had a possible lacunar infarction, and 11 (10.4%) had a stroke of undetermined etiology. Besides the presence of significant carotid stenosis (p<0.001), none of the variables related to stroke were different among the sub-groups.

CONCLUSION: Patients with significant carotid stenosis were more likely to develop atherothrombotic stroke, while other risk factors associated with stroke failed to point to an etiologic cause. It should also be emphasized that the conventional classification system failed to aid in the correct diagnosis and risk stratification in patients with multiple confounding risk factors.